Scleral clip and procedures for using same

ABSTRACT

A method and clip for treating presbyopia and/or open angle glaucoma in which the sclera is supported or reinforced, while substantially maintaining the special relationship between the ciliary muscle and the lens. The method includes making an incision in the conjunctiva to gain access to the sclera overlying the ciliary muscle. The Tenon&#39;s capsules are moved laterally to expose the sclera, and the sclera is extended outwardly. A clip, or series of clips, is provided having two closeable arms for engaging the outwardly-extended sclera therebetween. The arms of the clip are closed on the sclera so as to grasp a portion of the sclera, and then the Tenon&#39;s capsules are slid over the clip and the conjunctiva is closed.

The present invention is directed to a surgical method for treatingvision disorders, such as presbyopia and/or glaucoma, and to theassociated devices used in conjunction with the method.

BACKGROUND OF THE INVENTION

Presbyopia is a vision disorder associated with aging resulting from thefailure of the accommodation mechanism of the eye. The accommodativemechanism is driven principally by parasympathetic innervation of theciliary smooth muscle. In the non-presbyopic eye, this causes the muscleto slide forward in a unified manner and produces an inward movement ofthe muscle. The result is a reduction in the diameter of the ciliarymuscle collar that instigates a series of events leading to an abilityto see near objects clearly.

While it is clear that the capsular elasticity of the lens of the eye,i.e., the ability of the lens capsule to mold the lens, diminishes withage, the precise cause of presbyopia remains the subject of debate.

Presbyopia is most frequently treated by the use of reading glasses,bifocals, and progressive multi-focal contact lenses. However, theinconveniences associated with eyeglasses and contact lenses haveprompted investigation into, and the development of, surgical techniquesaimed at correcting presbyopia.

One such method is anterior ciliary sclerotomy (“ACS”). ACS is based onthe theory that accommodation results primarily from ciliary bodycontraction, with the resulting forward movement of the lens. Itsunderlying rationale is based on the observation that the lensconstantly grows throughout life, gradually crowding the posteriorchamber and eventually preventing full function of the ciliarybody/zonular complex. The “crowded” state causes the reduction of lenspower change with attempt at accommodation. ACS utilizes a series ofsymmetrical radial, partial-thickness scleral incisions to attempt tomake more room for the ciliary body—which in turn allows more space forthe lens—by expanding the globe in the area of the ciliary body.However, this procedure has many potential complications, ranging frominfection and hemorrhaging to perforation, which could result in retinaldetachment, iris injury or prolapse.

Another proposed method for surgical reversal of presbyopia is based onthe theory that presbyopia results when the distance between the ciliarybody and the equator of the lens and its capsule becomes less with ageas a result of the normal growth of the lens. Thus, under this theorypresbyopia is treated by increasing the effective working distance ofthe ciliary muscle. This is accomplished by implanting a series ofscleral expansion bands just below the surface of the sclera and outsidethe cornea. The bands stretch the sclera so that the diameter of thecircle describing the intersection of the plane of the ciliary body withthe sclera is slightly increased. See, U.S. Pat. Nos. 5,354,331 and5,489,299 to Schachar. However, at least one study has called intoquestion the accuracy of the theory on which scleral expansion surgeryis premised. See, Mathews, “Scleral Expansion Surgery Does Not RestoreAccommodation in Human Presbyopia,” Opthamology, Vol. 106, No. 5, May,1999, pages 873-877. This study concludes that, if scleral expansionsurgery does alleviate presbyopia, an explanation other than therestoration of accommodation needs to be found. Schachar also believesthat his scleral expansion bands may have utility in the treatment ofprimary open-angle glaucoma by restoring the level of force which theciliary muscle exerts on the trabecular meshwork, thus opening thedrainage pores and relieving the intra ocular pressure (IOP).

Regardless of the theory employed, there is a need for correctingpresbyopia without the use of eyeglasses or contact lenses through arelatively safe and simple procedure that is easily reversible. There isalso a need for treating glaucoma that is safe, effective, and simple.

Accordingly it is the principal object of the present invention toprovide a surgical method for the treatment of ophthalmic disorders thatcan be ameliorated by supporting or reinforcing the scleral.

More specifically, it is an object of the present invention to provide asurgical method for treating presbyopia and/or glaucoma.

It is a further object to provide such a method that has a reducedpotential for complications and is easily reversible.

It is a still further object of the invention to provide a clip uniquelysuited for use in the treatment of presbyopia and/or glaucoma.

SUMMARY OF THE INVENTION

These objects, as well as others which will become apparent uponreference to the following detailed description and accompanyingdrawings, are accomplished by a method for treating presbyopia andglaucoma in which the sclera is supported or reinforced, while thespecial relationship between the ciliary muscle and the lens issubstantially unchanged. Specifically, the method includes making anincision in the conjunctiva to gain access to the sclera overlying theciliary muscle. The Tenon's capsules are moved laterally to expose thesclera, and the sclera is extended outwardly. A clip, or series ofclips, is provided for grasping the outwardly-extended sclera. The clipincludes a series of teeth or similar structures that engage a portionof the sclera, thus securing the clip thereto, and then the Tenon'scapsules are slid over the clip and the conjunctiva is closed.Preferably, four such scleral clips are applied to the sclerasubstantially equally spaced about the lens between the medial,inferior, lateral and superior rectus muscles. When applied to thesclera, the clips serve to prevent the sclera from buckling undertension applied by the ciliary muscle when trying to accommodate the eyeto near vision.

In another aspect of the invention, a scleral clip is provided forapplying to the sclera. The clips have a length of typically between 4to 5 mm, and no longer than approximately 6.0 mm, so as to fit betweenadjacent rectus muscles. The clips are provided with means, such asteeth or spurs, for grasping—but not penetrating through—the sclera.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a horizontal sectional view of an eyeball.

FIG. 2 is an anterior view of the eye showing the extrinsic eye muscles.

FIG. 3 is a simplified diagram showing two scleral clips attached to aneye.

FIGS. 4-14 are views of clips of various configurations to be applied tothe sclera in accordance with the present invention.

DETAILED DESCRIPTION

The method of the present invention is based upon a theory for the causeof presbyopia different from those set forth above. Specifically,presbyopia is caused by the failure of the ciliary body to adjust thelens diameter in order to focus images onto the retina for closeobjects. The ciliary muscles change the lens diameter by using thesclera as a support or fixation structure. As the sclera of the eyeweakens due to age, the ciliary muscles lack the support needed in orderto alter the lens diameter for focusing on close objects. Thus, in orderto allow the ciliary muscle to alter the lens diameter to see closeobjects, the sclera must be supported or reinforced. Accordingly, amethod is provided that utilizes a unique clip for reinforcing thesclera, so as to form a stronger and more stable support for the ciliarymuscles. In effect, the sclera is strengthened, and the ciliary musclesare then able to again function properly to provide near vision.

It is believed that the method and its associated clip may also beadvantageously used for the treatment of open angle glaucoma. Glaucoma,like presbyopia, is an age-related disease and is caused by a buildup offluid pressure in the eye which damages the optic nerve. Over time,glaucoma destroys peripheral vision, thus shrinking the field of vision.In a healthy eye, the fluid produced by the ciliary tissues surroundingthe lens is drained out of the eye by a series of drainage canals aroundthe outer edge of the iris. With age, because the ciliary muscles lacksupport, they are less capable of maintaining these drainage canals inan open condition to allow free drainage of fluid. By tensioning thesclera according to the present method, the support is provided for theciliary muscles, and the tissues of the eye that provide for drainageare stretched, thus reducing blockage of the fluid drainage canals andfacilitating the drainage of fluid from the eye.

With reference to FIG. 1, there is seen a simplified sectional view of ahuman eye 10 having a lens 12 contained within a lens capsule 14. Theciliary body and ciliary muscle 16 are connected to the lens capsule 14and also to the choroid 18. The sclera 20 overlies the choroid 18 and,at the front of the eye, the ciliary muscles 16, and terminates in thescleral spur 22 at the cornea 24 of the eye. The conjunctiva 26surrounds the cornea 24 and overlies the bulbar sheath (or Tenon'scapsule) 28 which in turn, overlies the sclera 20 on the front of theeye 10. Blood is supplied to the sclera by arteries in the superior,inferior, medial and lateral rectus muscles 30, 32, 34, and 36respectively, best seen in FIG. 2.

In the method of the invention, the eye is treated by first making aseries generally linear incisions (such as incisions 38 in FIG. 2) inthe conjunctiva 26 to gain access to the sclera 20. Preferably, prior tomaking the incisions, a generally standard preoperative procedure isperformed that includes marking the limbus and cornea at 10:00, 2:00,5:00 and 8:00 with violet blue to indicate the location of theincisions.

The incisions 38 are made radially outwardly from the cornea so as togenerally bisect the area between the adjacent rectus muscles (e.g.,between the superior and medial rectus muscles 30, 34 as shown by theincisions 38 in FIG. 2). For each incision 38, an initial incision ismade to dissect to the conjunctiva 26, bypassing the Tenon's capsule 28.Then the incision is deepened to open the incision into the episclera,creating an incision of from 3 to 7 mm in length in the episclera. Theincision is opened and, if necessary, the Tenon's capsule 28 is thenmoved laterally to expose the sclera 20.

The sclera 20 is then extended outwardly either mechanically with, e.g.,a forceps, or by the application of a vacuum. A clip 40 is applied tothe outwardly-extended sclera so as to put the sclera 20 under tension.The Tenon's capsule 28 is then reapposed over the clip and theconjunctiva 26 closed. No suturing is needed as the conjunctive selfseals. The procedure is then repeated for each of the marked quadrantsso that four clips are applied to the eye equally spaced about thecornea 24 between the adjacent rectus muscles.

FIG. 3 is a simplified drawing showing two clips 40 attached to the eye10. The clips 40 grasp the sclera overlying the ciliary body 16 adjacentthe iris 39. The applied clips 40 have a generally low profile, closelyadhering to the curvature of the eye, thus providing reinforcement tothe sclera.

With reference to FIGS. 4-9, the clips for use in the procedure can takemany different forms. In general, it is contemplated that the clip 40will have an overall dimension of approximately 1.5-2.5 mm in height(h), 0.4-0.6 mm in thickness (t) and no longer than 5.0-6.0 mm in length(l). The size of the clip is constrained by the distance between theadjacent rectus muscles. Specifically, the intent is to have the clipfit between the rectus muscles, so as to not impede the flow of blood tothe eye through the arteries in the rectus muscles. Thus, instead of asingle clip having a length of approximately 5.0 to 6.0 mm, a series ofclips can be used the sum of whose total length fits between theadjacent rectus muscles. Of course, it is anticipated that the use of asingle clip of the appropriate length will allow the procedure to beperformed more easily and quickly.

As can be readily appreciated, the procedure can be simply reversed bymerely again gaining access to the sclera by making an incision in theconjunctiva over the clip, moving the Tenon's capsule to expose theclip, and then removing the clip. No incision into the sclera isrequired.

In each of the FIGS. 4-9, the clip 40 includes two arms 42, 44 joinedtogether for relative movement to each other. On the inside portions ofthe clip are teeth, serrations, spurs, barbs, fingers, points 46 orother structures or projections for engaging and securely holding orgripping the sclera to the arms of the clip as it is affixed to thesclera. The teeth 46 are sized to engage the sclera, but not be of asize or configuration to penetrate through the sclera (which might causeerosion of the sclera). Consequently, the teeth 46 may be as small as20-80 μm. The clips are originally in their “open” position and then“closed” on the sclera with a forceps or other applicator, the clipsremaining in their closed condition in the absence of an external forcebeing applied to separate the arms of the clip. It is contemplated thatthe arms of the clips will be closed on the order of 10 to 15 degrees.This should prolapse the uvea and move the sclera outward approximately0.5 mm, for a total of 2 mm if four clips are applied. This willincrease the amplitude of accommodation, thus reversing the effects ofpresbyopia. This outward movement of the sclera should also increase theangle of the canals of Schlemn, thus increasing the aqueous flow anddecreasing the intra-ocular pressure, to ameliorate the effects ofglaucoma. The clips 40 may be made of any biocompatible material,including tantalum, polymethyl methacrylate (PMMA), and, preferably,titanium, that has sufficient deformability and resiliencecharacteristics to permit the clip to be “opened” and then remain closedwhen applied to the sclera. Turning to FIG. 4, a first embodiment forthe scleral clip 40 is shown in which each of the legs 42, 44 is bowedinward so as to impart some resiliency to the clip 40. Each leg 42, 44also includes a series of teeth 46 for gripping into the sclera. Thescleral clip of FIG. 5 is similar to that of FIG. 4, except resiliencyis imparted to the clip 40 by having the legs 42, 44 bow outwardly.

FIG. 6 shows a further embodiment of a clip 40 that comprises a centralportion in the shape of a rectangle folded along a diagonal, with atooth 46 at each of the lower corners. A pair of staple-like membersalso having teeth 46 depend from the opposite ends of the rectangularportion so as to provide further means for gripping the sclera.

FIG. 7 illustrates a clip embodiment similar to FIGS. 3 and 4 exceptthat the clip 40 includes a resilient band 48 that connects one leg tothe other. The band 48 serves to keep tension on the legs 42, 44 of theclip when the teeth engage the sclera.

FIG. 8 shows a clip 40 that has a spider-like configuration with aplurality (4 shown) of legs depending from a central body, each legterminating in a tooth 46.

FIG. 9 shows a clip 40 similar to those of FIGS. 3, 4 5 and 6, exceptthat central portions of the clip 40 are removed to give it a fork-likeappearance.

FIG. 10 is a further embodiment of a scleral clip 40 according to thepresent invention that is similar to the clip of FIG. 7, except that itdoes not include the resilient tensioning band. The clip 40 includes anindentation 50 in the center of each arm 42, 44 for cooperation with atensioning instrument for application of the clip. Also, the teeth 46have a length of 200 μm and are rounded, beveled, or blunted, so as tonot present a sharp edge that could penetrate the sclera. The clip maybe provided with a latex-free silicone polymer or acrylic coating,preferably white in color, on the outer or upper surface thereof inorder to make the clip less conspicuous when attached to the eye.

FIGS. 11 a and 11 b are a perspective view and end view, respectively,of a further embodiment of a clip 40. This embodiment is similar to thatin FIG. 4, except that the arms 42, 44 are not bowed, but aresubstantially flat. The clip 40 is preformed so that the angle betweenthe two arms is approximately 175 degrees, so that, when applied to thesclera and the arms are closed 10 to 15 degrees, the angle between thearms is between approximately 160 to 165 degrees. This angle providesfor a clip that, when applied more closely approximates the curvature ofthe eyeball. This is likely to be perceived by the wearer as morecomfortable, and may also reduce any erosion of tissue that overlies theapplied clip. The angle of the teeth 46 to their respective arms 42, 44is approximately 90 degrees.

FIG. 12 is a perspective view of a clip 40 similar to that of FIGS. 11a, 11 b, except that the end portions of the arms 42, 44 are relievedinwardly at 52. This reduces the portion of the clip 40 that, whenattached to the eye, extends beyond the radius of curvature of the eye,to achieve the benefits of wearer comfort and reduction of tissueerosion discussed above.

FIG. 13 is a further embodiment of a clip 54 in accordance with thepresent invention. The clip 54 has the same overall dimensions as theclip disclosed above, i.e., approximately 3 to 5 mm by 5 to 6 mm, so asto fit between adjacent rectus muscles. However, the clip is oval orround in shape and has a central opening 56 enclosed by a continuousouter portion so that the clip 54 has a ring-like appearance. This clipis applied to the sclera by prolapsing the sclera through the centralopening in the clip by mechanical means, such as a twist hook orforceps, or by the application of a vacuum. One or both of the centralopening 56 or outer edge 58 may be provided with teeth 60, which aresimilar to teeth 46 described above, for securing the clip to thesclera. Further, the teeth may be bent out of the plane generallydefined by the clip so that they more firmly grip the sclera. Withreference to FIG. 14, the teeth on the outer edge or periphery 58 may bebent downwardly an angle α from between approximately 90 degrees toapproximately 135 degrees, while the teeth on the central opening orinner periphery 56 are bent downwardly an angle β between approximately20 degrees to 45 degrees.

The clip 54 is generally flat, with little or no angle between the twoarms or sides 62, 64, as defined by the center line through the clip,thus providing a very low profile. Preferably, the clip 54 issufficiently thin so that it conforms to the natural shape or curvatureof the eye.

Thus, a method and a clip for performing the method have been providedthat fully meet the objects of the present invention. While theinvention has been described in terms of a preferred method and clip,there is no intent to limit the invention to the same. Instead, theinvention is defined by the scope of the following claims.

1. A method of treating glaucoma in a eye having a lens, ciliary musclessuspending the lens, sciera having a surface overlying the ciliarymuscles and conjunctiva overlying the surface of the sciera comprisingthe steps of: making an incision in the conjunctiva to gain access tothe surface of the sclera overlying the ciliary muscle; exposing thesclera; providing a clip for attachment to the sclera so as to engagethe surface thereof and provide external support; securing the clip to aportion of the sciera to effectively shorten the portion of the scieraheld by the clip; and closing the conjunctiva over the clip.
 2. Themethod of claim 1 wherein the sclera is supported by a clip at least twolocations overlying the ciliary muscles.
 3. The method of claim 1wherein the sclera is supported by a clip at four locationssubstantially equally spaced about the lens.
 4. The method of claims 3wherein the sclera is supported by a clip that grips the sclera.
 5. Themethod of claim 1 wherein a plurality of clips are applied to thesclera.
 6. The method of claim 5 wherein at least four clips are appliedto the sclera substantially equally spaced about the lens.
 7. The methodof claim 1 wherein the clip is attached to the sciera without making anincision in the sciera.